[lifeline]

This should be an easy question, but I really have no clue.

Ok if I have 100ml of hydrogen peroxide and I'm told it's 50% pure, how do I confirm that. What's the formula?

And if I want to increase of decrease the purity how do I do that? (Is it by adding water for decrease and boiling it to evaporate water to increase)?

I apologise for the quesiton, I'm a novice.

[iceman]

search for it on www.google.com put in Hydrogen Peroxide Formula. and you should get all the answers your looking for

[constant thinker]

Or use wikipedia.
http://en.wikipedia.org/wiki/Hydrogen_Peroxide

Yes adding or removing water would change the concentration (purity) of the hydrogen peroxide in solution.

[Borek]

Yes adding or removing water would change the concentration (purity) of the hydrogen peroxide in solution.

It may be nit picking, but I don't think concentration and purity are interchangegable. Imagine 5% w/w solution of hydrogen peroxide, that contains nothing but H₂O₂ and H₂O. That's pure. Now add a pinch of - say - iron sulfate. It is still 5%, but it is by no means pure now.

So the bottom line is - define pure first, ask questions later

I suppose lifeline means just concentration, but who knows...

[mir]

Ok if I have 100ml of hydrogen peroxide and I'm told it's 50% pure, how do I confirm that.

You might try to titrate the solution of H₂O₂. You can't make the solution more concentarted by heating, when the H₂O₂ most likely will decomponate. And concentrate a peroxide? Who wanna do that? Remember Kursk...

[Borek]

decomponate

Good one

[lifeline]

I've tried google and wikipedia, and had no luck.

Yes what I should have said was 'concentration' and not 'purity'.

mir, I've read that you can increase the concentration through heating, but it's dangerous. But's that's not the problem I'm facing, as I'm more interested in decreasing the concentration, which is simple, but the problem is finding out the concentration of my solution.

Let's say I have a 30% solution of H₂O₂, I add some H₂O to the solution, now it's decreased in concentration, but how do I find out the exact concentration of my solution?

Is there some kind of formula to figure it out, possibly involving comparing the size (ml) to the weight (g)? As H₂O₂ weighs more than H₂O. Or is it guess work?

I really appreciate the help, thanks.

[Borek]

See lecture on dilutions. Note that you may need density tables - these are not calculated, but rather measured. Check my CASC (although I am not sure if free trial contains hydrogen peroxide table, I am afraid this one is available only in registered version).

[lifeline]

See lecture on dilutions. Note that you may need density tables - these are not calculated, but rather measured. Check my CASC (although I am not sure if free trial contains hydrogen peroxide table, I am afraid this one is available only in registered version).

Cheers, I'll have a look anyway 

[mir]

decomponate

Good one

I speak Norwenglish, not English, doh!

[Borek]

TBH - I speak Polenglish